Abstract Bullying is an all too common occurrence in our nation?s schools. Research underscores how all involved? bullies, victims, and bystanders?are at elevated risk for negative outcomes in many aspects of a child?s social, emotional, and academic life. Recent reviews of school-based programs demonstrate that social emotional learning (SEL) is a critical ingredient in effective bullying prevention. Unfortunately, logistical barriers (e.g., time, cost, need for trained staff) too often undermine schools? abilities to implement traditional in-person programming with all students. This SBIR Phase project aims to apply cutting-edge intelligent social tutoring game technology to create a new, evidence-based serious game specifically designed to help late elementary students learn and build the social emotional skills needed to navigate bullying situations and successfully transition to the middle school social environment. The end result of our Phase I and Phase II efforts will be a rigorously tested serious game specifically designed to prevent bullying and prepare students socially for the middle school transition through a safe virtual environment where late elementary students can learn and practice essential SE skills for identifying, managing, and avoiding a variety of bullying situations. In Phase I, we will accomplish three specific aims. First, we will create a serious game prototype with input from 4th and 5th grade students, parents, and educators to select the custom graphic design and storyworld and inform development of five social problem solving scenes depicting various types of bullying situations (i.e., physical, verbal, relational, cyber, and bystander). Second, we will conduct feasibility tests with 4th and 5th grade students and educators who will review and evaluate the prototype. And, third, we will create a full Phase II development and testing plan based on our Phase I findings. Our proposed serious game bullying prevention product will meet a significant market need as the first rigorously tested serious game for bullying prevention to prepare students socially for the difficult transition to middle school. Importantly, the proposed product will benefit from an established channel into the school market as our commercialization partner, Personalized Learning Games, Inc., has committed to include the proposed game in its product line, once fully developed and tested in Phase II.